1. Field of the Invention
The invention relates to an X-ray apparatus which comprises a hydraulic system for counterbalancing and for displacing an apparatus section said hydraulic system comprising a cylinder with two cylinder chambers whose volumes vary in the opposite sense upon displacement of the apparatus section and which can be coupled to a hydraulic drive via a respective hydraulic line.
2. Description of the Related Art
An X-ray apparatus of this kind is known from U.S. Pat. No. 4,964,149. Therein, the two hydraulic lines communicate, via valves, with a respective reservoir whose size must be sufficient to receive the maximum volume of the associated cylinder chamber. Each reservoir comprises a diaphragm which separates the hydraulic liquid from an air cushion whose pressure can be controlled by means of an operator handle on the apparatus section to be displaced. The known hydraulic system enables counterbalancing and displacement of the apparatus section even when the X-ray apparatus has been rotated through 180.degree. about a horizontal axis, so that the force of gravity acting on the apparatus section changes its direction by 180.degree.. However, the structural volume of the hydraulic system is liable to become comparatively large, notably because of the reservoirs, when the apparatus section is heavy and excessive pressures are to be avoided in the hydraulic system.